Imaging the Solar Corona from “Within”: A Cutting-edge Approach to Enhance PSP/WISPR Imagery

The unprecedented remote-sensing observations obtained by the Wide Field Imager for Solar Probe (WISPR) on board the Parker Solar Probe (PSP) from distances inside Mercury’s orbit are revolutionizing our perception of the fine-scale morphology and evolution of the solar corona. For the first time, the inherent limitations of 1 au observations arising from the superposition of optically thin features along the long lines of sight are being overcome by observing from “within.” The richness of information makes the interpretation of the coronal scene highly subject to the processing performed on the images to remove the background, i.e., the bright, constant emission from interplanetary dust (F-corona). Several customized techniques to reveal the faint, solar-outflowing plasma and the large-scale K-corona structures have already been developed for WISPR. They differ on how the background is estimated. None, however, excels at revealing the faint and diffuse K-corona brightness component that permeates the scene. In this paper, we introduce a new, heuristic approach to model the evolution of the F-corona background as a function of the observer’s location. The methodology exploits WISPR data sets from PSP encounters that share the same orbital parameters. The resulting background-removed data products unveil the morphology and dynamics of the large-scale K-corona with superb clarity and demonstrate that the scientific interpretation of the coronal scene in WISPR images relies on the complementary vision provided by the existing methodologies.